1. Field of the Invention
The present invention relates to the field of photoprotective compounds, and more particularly to photoprotective compounds from plant oil processing.
2. Background Art
Pesticides, herbicides, xenobiotics and other useful chemicals are commonly applied to fields, forests, roadsides and other locations where they may be degraded by exposure to light. Similarly, living organisms including bacteria, bacterial spores, fungi, fungal spores, viruses and viral spores are increasingly being applied in the environment for their beneficial effects. Exposure of these materials and beneficial organisms to light often decreases their effectiveness by altering their chemical structures or diminishing their biological activity. Photoprotective strategies can be employed to maintain or increase the effectiveness of these compounds and organisms.
Wood, plastic, fabric and many other construction materials are also degraded by visible and ultraviolet light. Over time exposure to light will fade or discolour such materials and decrease their integrity. Photoprotective strategies may also be employed to maintain the integrity and appearance of these materials.
Virus particles may be mixed with opaque solids such as carbon black to maintain viability by protection from white light in the method of U.S. Pat. No. 3,541,203. U.S. Pat. No. 5,939,089 teaches methods of coating viral spores with kraft lignin. The coated virus spores possess enhanced resistance to ultraviolet light.
Insecticide compositions containing pyrethinoids are highly susceptible to light degradation. According to U.S. Pat. No. 3,264,176 insecticide powders may be stabilised against light degradation by absorption onto charcoal. The disadvantage of this method is the tendency of dark materials to heat in the environment. Heat as well as light exacerbates the processes involved in degradation and inactivation. Reflective pigments including titanium dioxide can be used in place of carbon black according to U.S. Pat. No. 2,168,064 but the added cost of these materials limits their application. Dextrins and gums also provide protection to pyrethinoids. (U.S. Pat. No. 3,130,121). Strong UV absorbing compounds may be mixed with pyrethinoids to maintain activity. Diisophorone, for example, may be mixed with pyrethinoids to protect them from light wavelengths between 210 and 350 nm according to U.S. Pat. No. 3,839,561. Pyrethinoids may also be stabilized by the addition of amyl-paradimethylamino benzoate and a suitable antioxidant (U.S. Pat. No. 3,560,613).
Endosulfan and chlorpyriphos are also noted to be unstable to light exposure. U.S. Pat. No. 5,549,903 teaches of the use of urea encapsulation and light absorbing compounds to produce a stabilized insecticide product.
Petroleum spray oils may be used to control a number of fungi and insects (U.S. Pat. No. 3,098,000) but these oils are subject to harmful oxidation catalyzed by ultraviolet light. Degradation of the oils causes them to become phytotoxic.
Combinations of anti-oxidants and light absorbents may be added to the oils to prevent degradation and phytoxicity.
Synthetic light absorbing compounds may be highly effective but they are produced from non-renewable resources and they may have undesirable side effects. For example, U.S. Pat. No. 2,772,198 demonstrates that 4-amino-azo-benzene provides excellent protection of pyrethinoids but this compound is a potent carcinogen. Acidulated soybean and other acidulated vegetable oils are commonly used as adjuvants for herbicidal compounds. Gednalske reported that blends of a non-ionic surfactant and acidulated soapstock were effective in preparing a carrier solution for the application of herbicides (U.S. Pat. No. 5,260,260). U.S. Pat. No. 5,521,144 teaches that mixed tocopherols may be added to acidulated soapstock to improve the environmental stability of active ingredients applied with the adjuvant. Acidulated soapstock may also be used in herbicidal compositions to decrease odours as taught by Gednalske and Herzfeld (U.S. Pat. Nos. 5,463,180 and 5,719,102).
Soapstock is a co-product obtained in the manufacture of vegetable oil. It is commonly used in wide-ranging applications including animal feed and road dust control. Industrial soapstock is a highly variable product, which contains significant amounts of pigments, colour bodies and other compounds. Acidulated soapstock is prepared by adding acid to soapstock and recovering oil from the acidified solution. The acidulated oil solution is a concentrated source of plant pigments.